1. Field of the Invention
This invention generally relates to semiconductor manufacturing equipment and, more particularly, to a gate valve for use with a rapid thermal processing reactor.
2. Description of Related Art
In the semiconductor industry, to continue to make advancements in the development of semiconductor devices, especially semiconductor devices of decreased dimensions, new processing and manufacturing techniques have been developed. One such processing technique is known as Rapid Thermal Processing (RTP), which reduces the amount of time that a semiconductor device is exposed to high temperatures during processing. The RTP technique typically includes irradiating the semiconductor device or wafer with sufficient power to quickly raise the temperature of the wafer and hold it at that temperature for a time long enough to successfully perform a fabrication process, while avoiding such problems as unwanted dopant diffusion that would otherwise occur at the high processing temperatures.
As is widely known in the semiconductor processing industry, processing techniques such as RTP require fabrication clean room space to ensure that the processing is free from contaminants and particles that may reduce manufacturing precision. However, clean room space is expensive both to construct and maintain. Thus, semiconductor wafer processing systems which require large footprints are economically disadvantageous. Accordingly, processing system designers have attempted to construct systems having components with smaller, more compact, and narrower structures.
Gate valve structures may be used in the processing system to isolate semiconductor wafers in various chambers, as the wafers are transported between locations of a first pressure to areas of a second pressure. Although, the concept of isolating or sealing a chamber using gate valves is straightforward, the design of such valves can be complicated, especially due to competing design considerations. For example, the gate valve must provide adequate positive closure that can withstand process pressure and vacuum. Most often this need has been met using complicated linkages that typically require both an axial and a lateral sealing action. For example, an apparatus is disclosed in U.S. Pat. No. 4,721,282 where an initial axial motion of a shaft provides for the primary movement of a gate member toward a processing chamber port. A secondary lateral motion provides for movement of the gate member against the port for a positive seal.
To conserve clean-room space and provide access to a process chamber, what is needed is a gate valve, which occupies a relatively small volume to maintain a small processor footprint and provides adequate isolation to the process chamber of a processing system during semiconductor processing.
In accordance with the invention, a valve assembly includes a main body defining a central axis and a gate. The gate includes a curved surface relative to the central axis and the gate is disposed within the main body. The gate is rotatable about an axis of rotation running along the length of the gate. The valve assembly also includes an actuation assembly for rotating the gate about the axis of rotation between a first position where said valve is open and a second position where said valve is closed.
This invention will be more fully understood in light of the following detailed description taken together with the accompanying drawings.